The tickets are in goody bags given out at the entrance of the 24-25 June Stoneleigh show.
The HTA will be celebrating the 58 nurseries that have exhibited for all five years of the event.
One trade launch is Eryngium Neptune's Gold, which will be shown jointly by Lovania Nurseries and Seiont Nurseries, in an unusual joint launch.
The HTA is also running a 'Plant Selfies' photo competition and for visitors to vote for their favourite plants. Take a photo on your phone or digital camera and email it to firstname.lastname@example.org stating your name, company, email and category.